Method for molding three-dimensional foam products using a continuous forming apparatus

ABSTRACT

A continuous forming apparatus for molding foam material into foam products that includes a first endless belt and a second endless belt that cooperates with the first endless belt to mold the foam material. The continuous forming apparatus may also include a first plurality of cleats and a second plurality of cleats opposed to the first plurality of cleats that support the first endless belt and the second endless belt respectively. The first plurality of cleats may include a three-dimensional abutment surface that provides transverse and lateral support to the first endless belt. Additionally, the continuous forming apparatus may include a first frame disposed to support the first plurality of cleats, a second frame disposed to support the second plurality of cleats, and a drive mechanism for imparting motion to the first endless belt, the second endless belt, the first plurality of cleats, and the second plurality of cleats.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/165,071, filed Jun. 23, 2005, which claims priority benefitunder 35 U.S.C. § 119(e) from U.S. Provisional Application No.60/585,420, filed Jun. 24, 2004. The present application incorporatesboth documents herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to continuous forming apparatusand methods for forming foam materials into three-dimensional shapes.Generally, the production of three-dimensional products made from a foammaterial requires a mold that can both define the three-dimensionalshape and contain any pressure exerted by the foam material until theproduct is rigid enough to be removed from the mold.

To accomplish these requirements, currently available productionapparatus for continuous production include endless flexible mold beltsand chain-mounted rigid mold sections. Endless flexible mold belts thatare used to form 3-D products on a continuous basis may be done byarranging one or more flat belts edge to edge so as to form a cavity, orby using two thicker belts, arranged face to face, with a crosssectional shape extending into one or both of the belt faces. As usedherein, the term “flat” means relatively flat so that a flat surface maybe rough and include any type of surface finish.

The belts may be incorporated into a motorized forming apparatus similarto a conveyor belt machine. The belts are typically fabric-reinforced,and may be faced with an elastomeric, contoured face so as to allow themolding of deeper features and to provide the mold belt with sufficientflexibility to bend around the pulleys of the motorized formingapparatus. An extruder or other delivery system may be used to delivermaterial into one end of a forming apparatus where it is held andconveyed within a mold belt cavity until the material is sufficientlycured or cooled to maintain its shape after being expelled from theapparatus. These currently available belt-driven continuous formingapparatus are typically used to produce small cross sectional areaproducts.

The production of parts with larger cross sections or deeper surfacedetail typically requires the use of a machine that utilizeschain-mounted rigid mold sections. For example, foam parts with surfacedetail like imitation wood beams are sometimes produced on a continuousbasis using these continuous forming apparatus. However, these machinesare extremely expensive and adjacent mold sections must fit togetherprecisely to prevent material from oozing and binding between moldsections.

Large foam buns are continuously cast in square forming machines thatare comprised of table-top conveyors using thin flat plates attached tochains. Multiple belts of flat plates are combined to make a continuoussquare cavity to support and mold the foam product. A wax paper orplastic film is used to prevent the foaming material from sticking toand leaking between the plates. The buns are then slit to makemattresses and the like.

While mold belts may define the desired three-dimensional product shape,they must be driven in the direction of production, and supported so asto contain the pressure of the foaming material without deforming.Typically, these belts are driven by a motorized pulley and supported byeither slider-beds or by support rollers in much the same way as aconventional conveyor belt. Slider-bed supported systems must overcomethe pressure-induced friction between the back of the belt and theslider-bed. The wider the product and longer the forming apparatus, thegreater the friction that the drive mechanism must overcome, whichlimits the practical size of a slider-bed supported forming apparatusfor foam materials.

Roller-supported mold belts minimize belt-to-bed friction, but the beltsare unsupported in the spans' between adjacent rollers, allowing thebelt to deflect outward. The roller-bed supported belts virtuallyeliminate the friction associated with slider-beds, but the foamingpressure on the belt is not supported between individual rollersallowing the belts to intermittently gap open as they travel.

The friction problem of the slider-bed may be mitigated by using airfilm lubrication. However, the foaming pressure is not constant alongthe length of the machine, especially for thermoset foams. Thus, airfilm lubrication requires the regulation of air pressure to discretepressure zones along the machine's length. Additionally, air filmlubrication is limited to smaller parts with low foaming pressures inorder to avoid using excessively high-pressure air.

Accordingly, a need exists for continuous forming apparatus that fullysupport high foaming pressures while the foam material cools and cures.Furthermore, a need exists for continuous forming apparatus thatexperiences minimal frictional forces so that the continuous formingapparatus is able to mold wider foam products without sacrificing thedimensional accuracy, surface detail, and desired cross section of thefoam product.

SUMMARY OF THE INVENTION

The apparatus of the present invention has been developed in response tothe present state of the art, and in particular, in response to theproblems and needs in the art that have not been fully solved bycurrently available continuous forming apparatus. Thus, the presentinvention provides a continuous forming apparatus for molding foamingmaterial into foam products.

In accordance with the invention as embodied and broadly describedherein in the preferred embodiment, a continuous forming apparatus isprovided. According to one embodiment, the continuous forming apparatusincludes a first endless belt for molding the foam material, a firstplurality of cleats, and a second plurality of cleats opposed to thefirst plurality of cleats.

The first endless belt may impart surface features or texture to theproduct surface, and may also incorporate non-stick films or compoundsas mold release agents. The first endless belt may be rolled or foldedso as to define a mold cavity. The mold belt cavity may impart any3-dimensional shape, profile, texture, or features into the foamproduct.

The first plurality of cleats may have a three-dimensional abutmentsurface to provide transverse and lateral support to the first endlessbelt. The first plurality of cleats may also be shaped to providetransverse and lateral support to the foam material as it cures and ismolded. The second plurality of cleats may have a flat abutment surfaceor a three-dimensional abutment surface depending on the size andcomplexity of the foam part to be molded.

The continuous forming apparatus may also include a drive mechanism forimparting motion to the first endless belt, the first plurality ofcleats, and the second plurality of cleats. The drive mechanism may beconnected to the first endless belt, the first plurality of cleats, andthe second plurality of cleats so that they move at the same speed. Bymoving at the same speed, the first plurality of cleats and the secondplurality of cleats may grip the first endless belt to provide constantsupport to the first endless belt as a molded foam product is cured andto reduce the friction resulting from moving the first endless belt.

The continuous forming apparatus may comprise a first attachment chainconnecting the first plurality of cleats together and a secondattachment chain connecting the second plurality of cleats together. Theattachment chains permit the plurality of cleats to form an endless loopthat provides constant support to the first endless belt as a moldedfoam product is cured. Furthermore, the attachment chains are used tospace each cleat of each plurality of cleats. The attachment chains keepeach cleat close to the adjacent cleats to support the endless beltswithout overlapping or binding with the adjacent cleats. By keeping eachcleat close to the adjacent cleats, the unsupported sections of theendless belts are kept to a minimum.

The continuous forming apparatus may also include a second endless beltthat cooperates with the first endless belt to mold the foam material.The second endless belt may be supported by the second plurality ofcleats. In some configurations, the second plurality of cleats mayinclude a three-dimensional abutment surface that grips the secondendless belt and provides transverse and lateral support to the secondendless belt. Together, the first endless belt and the second endlessbelt may define a mold cavity for forming a molded foam product. Theplurality of cleats supports the first endless belt and the secondendless belt against the high pressures that may be experienced as thefoam material is molded within the continuous forming apparatus.

The continuous forming apparatus may also include a third endless beltand a fourth endless belt that cooperate with the first endless belt andthe second endless belt to mold the foam material. The continuousforming apparatus may further comprise a third plurality of cleats and afourth plurality of cleats disposed generally orthogonal to the firstplurality of cleats and the second plurality of cleats. The thirdendless belt may be supported by the third plurality of cleats and thefourth endless belt may be supported by the fourth plurality of cleats.

In configurations where the third endless belt and the fourth endlessbelt are disposed orthogonally to the first endless belt and the secondendless belt, the continuous forming apparatus may be used toefficiently produce a range of simulated lumber products in sizes suchas 2.times.2, 2.times.4, 2.times.6, 2.times.8, 2.times.10, and2.times.12, by adjusting the distance between the third endless belt andthe fourth endless belt.

The continuous forming apparatus may have a third attachment chainconnecting the third plurality of cleats together and a fourthattachment chain connecting the fourth plurality of cleats together. Thethird and fourth pluralities of cleats help to control the distancebetween the third endless belt and the fourth endless belt over thelength of the continuous forming apparatus.

The first endless belt may include an insert support feature forpositioning inserts within the mold cavity prior to adding foam materialto the mold cavity. Furthermore, the first endless belt may comprise amold cavity for molding a discrete foam part. By forming a mold cavityshaped to mold a discrete foam part, discrete foam parts may be madeinexpensively on a continuous basis. Specifically, the first endlessbelt comprising a plurality of discrete mold cavities may producediscrete foam parts less expensively than using several discrete molds.

The first endless belt may also be supported by the first plurality ofcleats to form a curved cross sectional area for molding foam material.In some configurations, the first endless belt may also be supported bythe second plurality of cleats to form a circular cross sectional areafor molding foam material into a cylindrical product.

The continuous forming apparatus may also comprise a first framedisposed to support the first plurality of cleats and a second framedisposed to support the second plurality of cleats. The frames providesupport for the cleats to support the first and second endless belts andpermit the continuous forming apparatus to be used with foam materialsthat exert relatively high pressures against the mold such as thermosetplastics that are cured in an exothermic reaction and coupled with afoaming agent.

The frames also permit a transverse gap to be disposed between the firstplurality of cleats and the second plurality of cleats when the firstplurality of cleats supports the first endless belt for molding foammaterial. The gap is closed by one or more of the endless belts toprevent the foaming material from exiting the mold cavity. Additionally,leaving a small gap between the first plurality of cleats and the secondplurality of cleats may help to prevent the first plurality of cleatsfrom binding with the second plurality of cleats. The gap may range fromabout an inch to almost abutting but preferably is about 0.1 inches. Ofcourse, the first plurality of cleats may abut the second plurality ofcleats when the first plurality of cleats supports the first endlessbelt for molding foam material.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the above-recited and other featuresand advantages of the invention are obtained will be readily understood,a more particular description of the invention briefly described abovewill be rendered by reference to specific embodiments thereof which areillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered to be limiting of its scope, the invention will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings in which:

FIG. 1 is an elevated side view of a continuous forming apparatus withinthe scope of the invention;

FIG. 2 is a cross sectional view of the continuous forming apparatus ofFIG. 1 along line 2-2;

FIG. 3 is an alternative exploded cross sectional view of a cleat of afirst plurality of cleats, a cleat of a second plurality of cleats, afirst endless belt, and a second endless belt that may be used with thecontinuous forming apparatus of FIG. 1 taken along line 2-2;

FIG. 4 is a view of the first endless mold belt surface of FIG. 3 alongline 4-4 as supported by a first plurality of cleats;

FIG. 5 is an elevated side view of another continuous forming apparatuswithin the scope of the invention;

FIG. 6 is a cross sectional view of the continuous forming apparatus ofFIG. 5 along line 6-6;

FIG. 7 is an elevated side view of an alternative continuous formingapparatus according to the invention;

FIG. 8 is a top view of the continuous forming apparatus of FIG. 7;

FIG. 9 is a cross sectional view of the continuous forming apparatus ofFIG. 7 along line 9-9;

FIG. 10 is an alternative cross sectional view of a cleat of a firstplurality of cleats, a cleat of a second plurality of cleats, a firstendless belt, a second endless belt, a third endless belt, and a fourthendless belt that may be used with the continuous forming apparatus ofFIG. 7 taken along line 9-9;

FIG. 11 is a cross sectional view of the first endless mold beltsurface, a cleat of a first plurality of cleats, a second endless belt,and a third endless belt of FIG. 10 along line 11-11;

FIG. 12 is an elevated side view of an alternative continuous formingapparatus according to the invention;

FIG. 13 is a top view of the continuous forming apparatus of FIG. 12;

FIG. 14 is a cross sectional view of the continuous forming apparatus ofFIG. 12 along line 14-14;

FIG. 15 is an elevated side view of another continuous forming apparatusaccording to the invention;

FIG. 16 is a cross sectional view of the mold belt of FIG. 15 along line16-16;

FIG. 17 is a top view of the cross sectional view of FIG. 16 along line17-17; and

FIG. 18 is an exploded view of a cleat according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The presently preferred embodiments of the present invention will bebest understood by reference to the drawings, wherein like parts aredesignated by like numerals throughout. It will be readily understoodthat the components of the present invention, as generally described andillustrated in the figures herein, could be arranged and designed in awide variety of different configurations. Thus, the following moredetailed description of the embodiments of the continuous formingapparatus of the present invention, as represented in FIGS. 1 through18, is not intended to limit the scope of the invention, as claimed, butis merely representative of presently preferred embodiments of theinvention.

FIG. 1 is an elevated side view of a continuous forming apparatus 100according to the invention. The continuous forming apparatus 100receives foaming material from a feeder machine 102 in an input end 104,such as an extrusion machine or other feeding machine known in the art,for delivering foaming materials to the continuous forming apparatus 100by pouring, dropping, extruding, spreading, or spraying foaming materialonto or into the continuous forming apparatus 100. Once the foamingmaterial cures and moves through the molding section 105, it exits thecontinuous forming apparatus 100 as a foam product from the output end106 of the continuous forming apparatus 100.

Foaming materials may include but are not limited to thermoplastic andthermoset plastic compounds, highly-filled plastic compounds, compositematerials, elastomers, ceramic materials, and cementitious materialsthat may be mixed with a foaming agent known in the art.

The continuous forming apparatus 100 may include a support structure 108that supports and positions the components of the continuous formingapparatus 100 and a drive mechanism 110 for imparting motion to variouscomponents of the continuous forming apparatus 100. The drive mechanism110 may generally include a motor and gears for providing the variouscomponents of the continuous forming apparatus 100 with the correctforce and speed needed for the efficient operation of the continuousforming apparatus 100.

As shown, the continuous forming apparatus 100 has a longitudinaldirection 112 and a transverse direction 114.

The continuous forming apparatus 100 may also include a first endlessbelt 120 and a second endless belt 122 that is opposed to the firstendless belt 120. Together, the first endless belt 120 and the secondendless belt 122 define a mold cavity for defining the outsidedimensions of a foam product. In other words, the first endless belt 120and the second endless belt 122 contain and provide the foaming materialwith a final shape as it moves from the input end 104 to the output end106 of the continuous forming apparatus 100. Of course, the firstendless belt 120 and the second endless belt 122 may be covered withmold release to prevent the foaming material from sticking to theendless belts 120, 122.

The continuous forming apparatus 100 may also include a first pluralityof cleats 124 and a second plurality of cleats 126 opposed to the firstplurality of cleats 124. The first plurality of cleats 124 and thesecond plurality of cleats 126 engage and support the first endless belt120 and the second endless belt 122 respectively in molding the foamingmaterial into a foam product. The first plurality of cleats 124 and thesecond plurality of cleats 126 also prevent the first endless belt 120and the second endless belt 122 from deforming from the pressure exertedby the foaming material within the mold cavity.

The first plurality of cleats 124, the second plurality of cleats 126,the first endless belt 120, and the second endless belt 122 may bedriven or pulled by the drive mechanism 110 at the same speed or atdifferent speeds to move foaming material from the input end 104 to theoutput end 106 of the continuous forming apparatus 100. Alternatively,the first endless belt 120 and the second endless belt 122 may beun-powered or idle and driven by the first plurality of cleats 124 andthe second plurality of cleats 126. Of course, moving the firstplurality of cleats 124, the second plurality of cleats 126, the firstendless belt 120, and the second endless belt 122 at the same speedhelps to prevent damage to the first endless belt 120 and the secondendless belt 122 or the foam product held by the first endless belt 120and the second endless belt 122. By having the pluralities of cleats124, 126, move with the endless belts 120, 122, friction is reduced inthe continuous forming apparatus 100 so that the continuous formingapparatus 100 may use longer and wider endless belts than previouslypossible.

The first plurality of cleats 124 may be attached together by a firstattachment chain 128 to form an endless loop so that the first pluralityof cleats 124 may be positioned to continuously provide support to thefirst endless belt 120 as it molds foaming material. Similarly, thesecond plurality of cleats 126 may be attached together by a secondattachment chain 130 to form an endless loop so that the secondplurality of cleats 126 may be positioned to continuously providesupport to the second endless belt 122 as it molds foaming material.

The first attachment chain 128 and the second attachment chain 130 holdeach cleat of the first plurality of cleats 124 and the second pluralityof cleats 126, respectively, spaced at a desired distance to providesupport to the first endless belt 120 and the second endless belt 122without binding up against each other. When the first plurality ofcleats 124 and the second plurality of cleats 126 engage the firstendless belt 120 and the second endless belt 122, the first attachmentchain 128 and the second attachment chain 130 space the cleats of thefirst plurality of cleats 124 and the second plurality of cleats 126 sothat the longitudinal gap between each cleat is kept to a minimum toprovide a relatively continuous support surface. Generally, thelongitudinal gap may be about 0.1 inches, though the longitudinal gapmay be smaller or larger than this depending on the foaming pressures ofthe foaming material and the strength of the first endless belt 120 andthe second endless belt 122 to span the longitudinal gap withoutdeformation or opening of the mold cavity.

The continuous forming apparatus 100 may include a first frame 132 and asecond frame 134 that may be attached to the support structure 108. Thefirst frame 132 and the second frame 134 may include rigid slide railsor similar features that engage the first plurality of cleats 124 andthe second plurality of cleats 126. The first frame 132 and the secondframe 134 help to position the first plurality of cleats 124 and thesecond plurality of cleats 126 to support and engage the first endlessbelt 120 and the second endless belt 122. Additionally, the first frame132 and the second frame 134 help to close the first plurality of cleats124 with the second plurality of cleats 126 about the first endless belt120 and the second endless belt 122.

More specifically, compressive loads from the foaming material may pressthe first endless belt 120 and the second endless belt 122 into thefirst plurality of cleats 124 and the second plurality of cleats 126,respectively. The normal loads that would tend to separate the opposingfirst plurality of cleats 124 and the second plurality of cleats 126 arereacted through the first attachment chain 128 and the second attachmentchain 130 to the first frame 132 and the second frame 134. To minimizefriction, the first attachment chain 128 and the second attachment chain130 may include rolling elements that contact the first frame 132 andthe second frame 134.

The first attachment chain 128 and the second attachment chain 130 alsoprovide a structure strong enough to permit the drive mechanism 110 tomove the first plurality of cleats 124, the second plurality of cleats126, the first endless belt 120, and the second endless belt 122 fromthe input end 104 to the output end 106 of the continuous formingmachine 100. In some configurations, positive drive engagement isprovided by the use of sprockets in the drive mechanism 110 that engageand move the chain links.

A speed-controlled motor may be mechanically linked to a sprocket in thedrive mechanism 110 to drive the continuous forming apparatus 100.Furthermore, a single motor may be mechanically linked to one or more ofthe first plurality of cleats 124, the second plurality of cleats 126,the first endless belt 120, and the second endless belt 122.Alternatively, the drive mechanism 110 may include separate motors thatare electronically linked that permit the motors to operate at a similarspeed to drive two or more of the first plurality of cleats 124, thesecond plurality of cleats 126, the first endless belt 120, and thesecond endless belt 122.

The continuous forming apparatus 100 may further include pulleys orsprockets 136 for positioning the first plurality of cleats 124, thesecond plurality of cleats 126, the first endless belt 120, and thesecond endless belt 122 relative to each other and the first frame 132and the second frame 134. Additionally, once a cleat of the plurality ofcleats 124, 126 or a portion of one of the endless belts 120, 122 reachthe output end 106 of the continuous forming apparatus 100, the cleat orportion rounds a respective pulley or sprocket 136 and returns outsideof the molding section 105 to the input end 104 of the continuousforming apparatus 100. At the input end 104 of the continuous formingapparatus 100 new forming material is picked up by the first endlessbelt 120 and the second endless belt 122, the first plurality of cleats124 and the second plurality of cleats 126 engage and support the firstendless belt 120 and the second endless belt 122, and the foamingmaterial is transported through the molding section 105.

FIG. 2 is a cross sectional view of the continuous forming apparatus 100of FIG. 1 along line 2-2. In conjunction with FIG. 1, the continuousforming apparatus 100 has a transverse direction 114 and a lateraldirection 138.

As shown, the first endless belt 120 and the second endless belt 122cooperate to form a mold cavity 140, in which foaming material 142 isbeing molded to have a generally rectangular profile. The first endlessbelt 120 and the second endless belt 122 may be mirrors of each other sothat the first endless belt 120 and the second endless belt 122 eachdefine half of the mold cavity 140.

The first endless belt 120 and the second endless belt 122 may each havea three dimensional molding surface 144 that may be made of anelastomeric material 146 and may comprise fiber reinforcement 148. Theelastomeric material 146 is flexible to permit the first endless belt120 and the second endless belt 122 to bend around the pulleys 136 ofFIG. 1. The elastomeric material 146 may include a filler material toimprove its thermal conductivity.

The first endless belt 120 and the second endless belt 122 may includesidewalls 150. As the first endless belt 120 and the second endless belt122 are brought together, the sidewalls 150 abut each other to seal themold cavity 140 closed and prevent the foaming material 142 from leakingfrom the mold cavity 140.

The fiber reinforcement 148 provides the first endless belt 120 and thesecond endless belt 122 with enough longitudinal strength to resistbreakage due to the stresses imparted during the molding process, movingover the pulleys, and engaging the first plurality of cleats 124 and thesecond plurality of cleats 126. The fibers may include cotton, aramid,polyester, nylon, carbon fiber, and may include metal threads.Furthermore, the fibers may provide other benefits to the first endlessbelt 120 and the second endless belt 122 such as improved thermalconductivity.

Improving the thermal conductivity of the first endless belt 120 and thesecond endless belt 122 may improve its useful life by preventingthermal degradation of the elastomeric material 146 over time.Additionally, cooling the first endless belt 120 and the second endlessbelt 122 as they return to the input end 104 shown in FIG. 1 may alsoimprove the useful life of the first endless belt 120 and the secondendless belt 122.

In some applications of the invention, the first endless belt 120 andthe second endless belt 122 may be heated to improve the molding of somefoaming materials 142. For example, a thermoset foaming material 142 maycure faster with heat so that by heating the first endless belt 120 andthe second endless belt 122 a faster production rate may be achieved.Additionally, thermoplastic foaming material 142 may cool too quicklyupon contacting the first endless belt 120 and the second endless belt122, which may result in an undesirable surface finish such assharkskin. Heating of the first endless belt 120 and the second endlessbelt 122 may be provided by warm air or by radiant heat sources known inthe art, such as heat lamps.

To help prevent the first endless belt 120 and the second endless belt122 from deforming under the pressure exerted by the foaming material142 as they move through the molding section 105, the first plurality ofcleats 124 and the second plurality of cleats 126 each respectivelyengage and support the first endless belt 120 and the second endlessbelt 122. The first plurality of cleats 124 and the second plurality ofcleats 126 may each include a three dimensional abutment surface 152. Asthe first endless belt 120 and the second endless belt 122 engage thefirst plurality of cleats 124 and the second plurality of cleats 126,the first endless belt 120 and the second endless belt 122 are pressedinto and fully supported by the three dimensional abutment surfaces 152.

A transverse gap 154 may exist between the first plurality of cleats 124and the second plurality of cleats 126 to prevent the first plurality ofcleats 124 and the second plurality of cleats 126 from binding togetherand to assure that the first endless belt 120 and the second endlessbelt 122 are closed tightly together. The gap 154 may be about 0.1inches, but may be larger or smaller depending on the adjustments to thecontinuous forming apparatus 100.

The first plurality of cleats 124 and the second plurality of cleats 126may be made of a rigid material such as metal, rubber, ceramic, plastic,or a composite material. Each cleat of the first plurality of cleats 124and the second plurality of cleats 126 may be made by machining,casting, extrusion, molding, or any other material forming process knownin the art.

Each cleat of the first plurality of cleats 124 may be connectedtogether by the first attachment chain 128. Additionally, each cleat ofthe second plurality of cleats 126 may be connected together by thesecond attachment chain 130.

The first attachment chain 128 and second attachment chain 130 mayinclude support rollers 156 that engage rails 158 of the first frame 132and the second frame 134. The rollers 156 and the rails 158 minimize thefriction between the moving first plurality of cleats 124 and the movingsecond plurality of cleats 126 and the stationary first frame 132 andsecond frame 134. The rails 158 also align the first plurality of cleats124 with the second plurality of cleats 126. Furthermore, the rails 158prevent lateral motion of the first plurality of cleats 124 and thesecond plurality of cleats 126, which may damage a foam product orinadvertently open the mold cavity 140.

FIG. 2 also shows the first plurality of cleats 124, the secondplurality of cleats 126, the first endless belt 120, and the secondendless belt 122 returning to the input end 104 of the continuousforming machine and positioned outside of the molding section 105.

Referring to FIG. 3, an exploded cross sectional view of FIG. 1 takenalong line 2-2 illustrates an alternative first endless belt 170, asecond endless belt 172, and a first plurality of cleats 174, a secondplurality of cleats 176 that may be used with the continuous formingapparatus 100. As shown, the first endless belt 170 includes a threedimensional molding surface 178 that may include curves and may be usedto produce crown molding or other foam product. The first endless belt170 also includes sidewalls 150 for engaging and sealing against thesecond endless belt 172.

The first endless belt 170 and the second endless belt 172 may be madeof an elastomeric material 146 that permits the first endless belt 170and the second endless belt 172 to round the pulleys 136 of FIG. 1without cracking and breaking. The first endless belt 170 and the secondendless belt 172 may also includes fiber reinforcement 148 for providingthe longitudinal strength that permits the first endless belt 170 andthe second endless belt 172 to experience the longitudinal stresses ofbeing pulled around the continuous forming apparatus 100.

The second endless belt 172 may include a flat molding surface 180 thatcloses a mold cavity 182 formed by the first endless belt 170. In thisconfiguration, the mold features are mostly determined by the firstendless belt 170 which may provide some cost savings to manufacturers byrequiring a change of only the first endless belt 170 to change theprofile of the mold cavity 182.

The first plurality of cleats 174 may include a three-dimensionalabutment surface 184 that engages and supports the first endless belt170 against the second endless belt 172. The second plurality of cleats176 may include a flat abutment surface 186 that engages and supportsthe second endless belt 172 against the first endless belt 170.

FIG. 4 is a top view of FIG. 3 along line 4-4 that illustrates the firstendless belt 170 and the first plurality of cleats 174. As shown, thefirst plurality of cleats 174 has engaged and is supporting the firstendless belt 170.

The cleats of the first plurality of cleats 174 may be spaced from eachother by a longitudinal gap 190. The longitudinal gap 190 may range fromabout an inch or more to almost abutting an adjacent cleat, but maypreferably be about 0.1 inches which may be large enough to prevent thefirst plurality of cleats 174 from binding together as they move overthe continuous forming apparatus. Additionally, the gap 190 may be smallenough that the first endless belt 170 does not deform in the gap 190sufficiently to significantly affect the profile of the mold cavity 182.

As shown, the first endless belt 170 includes discrete mold cavities 182that are separated by a mold wall 192 of the first endless belt 170. Themold wall 192 separates the discrete mold cavities 182 and may assist inremoving a foam product from a mold cavity 192.

FIG. 5 is an elevated side view of another continuous forming apparatus200 according to the invention. As shown, the continuous formingapparatus 200 is similar to the continuous forming apparatus 100 of FIG.1 but includes a single endless belt 202 that is engaged and supportedby a first plurality of cleats 204 and a second plurality of cleats 206.Furthermore, the continuous forming apparatus 200 may also includepositioning rollers 208 that help form the endless belt 202 so that itmay engage and be supported by both the first plurality of cleats 204and a second plurality of cleats 206.

A foam product 207 is also shown exiting the output end 106 of thecontinuous forming apparatus 200.

FIG. 6 is a cross sectional view of the continuous forming apparatus 200of FIG. 5 along line 6-6 that further illustrates how the endless belt202 engages and may be supported by both the first plurality of cleats204 and the second plurality of cleats 206. Specifically, the endlessbelt 202 has a flat molding surface 208 and a length 210 that issufficient to permit the endless belt 202 to be rolled into a circularconfiguration where a first side edge 212 of the endless belt 202contacts and seals against a second side edge 214 of the endless belt202. Of course, other cross sectional shapes besides circles may beformed, such as ovals and polygons.

When the endless belt 202 engages the first plurality of cleats 204 andthe second plurality of cleats 206, the first side edge 212 and thesecond side edge 214 are positioned away from the transverse gap 154 andadjacent to one of the curved three dimensional abutment surfaces 216 ofthe first plurality of cleats 204 and the second plurality of cleats206. The curved three dimensional abutment surfaces 216 provide supportto the endless belt 202 in both lateral direction 138 and the transversedirection 114. Similarly, the endless belt 202 supports a foamingmaterial 218 in both lateral direction 138 and the transverse direction114.

Once the foaming material 218 is molded into the foam product 207 shownin FIG. 5, the endless belt 202 may be flattened and returned to theinput end 104 of the continuous forming apparatus 200 of FIG. 5 where itis re-rolled and reengages the first plurality of cleats 204 and thesecond plurality of cleats 206.

FIG. 7 is an elevated side view and FIG. 8 is a top view of analternative continuous forming apparatus 250 according to the invention.As shown in FIGS. 7 and 8, the continuous forming apparatus 250 issimilar to the continuous forming apparatus 100 of FIG. 1 and includes afirst endless belt 252, a second endless belt 254, a first plurality ofcleats 256, and a second plurality of cleats 258.

However, the continuous forming apparatus 250 may also include a thirdendless belt 260 and a fourth endless belt 262 that is opposed to thethird endless belt 260. The third endless belt 260 and the fourthendless belt 262 may be disposed substantially orthogonal to the firstendless belt 252 and a second endless belt 254.

Additionally, the continuous forming apparatus 250 may also include amold release application device 264. The mold release application device264 may mist, spray, brush, or in any other manner known in the artapply a mold release agent to the first endless belt 252, the secondendless belt 254, the third endless belt 260, and the fourth endlessbelt 262.

Furthermore, the continuous forming apparatus 250 may include atemperature control system 266. The temperature control system 266 maybe used to preheat the first endless belt 252, the second endless belt254, the third endless belt 260, and the fourth endless belt 262 inpreparation for molding foaming material with the continuous formingapparatus 250. The temperature control system 266 may also be used tocontrol the temperature of the first endless belt 252, the secondendless belt 254, the third endless belt 260, and the fourth endlessbelt 262 while the continuous forming apparatus 250 is in operation.

The temperature control system 266 may include heated air, heat lamps,or other sources of radiant energy for heating the first endless belt252, the second endless belt 254, the third endless belt 260, and thefourth endless belt 262. Additionally, the temperature control system266 may include fans, air conditioners, and evaporative coolers forproviding cool air flow to cool the first endless belt 252, the secondendless belt 254, the third endless belt 260, and the fourth endlessbelt 262. The temperature control system 266 may also include nozzlesfor spraying or misting a coolant, such as water, onto the first endlessbelt 252, the second endless belt 254, the third endless belt 260, andthe fourth endless belt 262.

FIG. 9 is a cross sectional view of the continuous forming apparatus 250of FIG. 7 along line 9-9. As shown, the first endless belt 252, thesecond endless belt 254, the third endless belt 260, and the fourthendless belt 262 cooperate to define a mold cavity 270 for molding thefoaming material 272. The first endless belt 252, the second endlessbelt 254, the third endless belt 260, and the fourth endless belt 262include flat molding surfaces 274 used to support the foaming material272 on one side.

By using four endless belts 252, 254, 260, and 262, the thickness of theendless belts 252, 254, 260, and 262 is kept to a minimum which reducesthe stress that the endless belts 252, 254, 260, and 262 undergo as theywrap around the pulleys of the continuous forming apparatus 250. Byreducing the stresses on the endless belts 252, 254, 260, and 262, theuseful life of the endless belts 252, 254, 260, and 262 may be extended.Additionally, the endless belts 252, 254, 260, and 262 may be made ofother materials than elastomers, such as metals, polymers, composites,and fabrics. Furthermore, by using four endless belts 252, 254, 260, and262, larger profiles of the mold cavity 270 are possible than using twoendless belts incorporating sidewalls.

The first plurality of cleats 256 and the second plurality of cleats 258each include a three dimensional abutment surface 278 for abutting andsupporting the first endless belt 252, the second endless belt 254, thethird endless belt 260, and the fourth endless belt 262. As shown, thefirst plurality of cleats 256 and the second plurality of cleats 258mirror and oppose each other in supporting the mold cavity 270. Becausethe first plurality of cleats 256 and the second plurality of cleats 258include a three dimensional abutment surface 278, the first plurality ofcleats 256 and the second plurality of cleats 258 are able to providesupport in the lateral 138 and transverse 114 directions.

FIG. 10 is an alternative cross sectional view taken along line 9-9 ofFIG. 7 illustrating a first plurality of cleats 280, a second pluralityof cleats 282, a first endless belt 284, a second endless belt 286, athird endless belt 288, and a fourth endless belt 290 that may be usedwith the continuous forming apparatus 250. As shown, the first endlessbelt 284, the second endless belt 286, the third endless belt 288, andthe fourth endless belt 290 may include flat molding surfaces 292. Thefirst endless belt 284 and the second endless belt 286 may also includeseparation features 294 for facilitating the separation of a foamproduct into discrete foam products.

Additionally, the first plurality of cleats 280 and a second pluralityof cleats 282 include three dimensional abutment surfaces 296. The threedimensional abutment surfaces 296 permit the first plurality of cleats280 to contact and support the first endless belt 284, the third endlessbelt 288, and the fourth endless belt 290, while the second plurality ofcleats 282 contacts and supports the second endless belt 286 in thelateral 138 and transverse 114 directions.

In this configuration, the first plurality of cleats 280 defines amajority of the mold cavity 270. Thus, only the first plurality ofcleats 280 may need to be changed in order to change the profile of themold cavity 270.

FIG. 11 is a cross sectional view of FIG. 10 along line 11-11 andillustrates the positioning of the separation features 294 on the firstendless belt 284. The separation features 294 form holes in a foamproduct which weakens the foam product at the location of the separationfeatures 294, permitting the foam product to be selectively broken atthe separation features 294.

FIG. 12 is an elevated side view of an alternative continuous formingapparatus 300 according to the invention. As shown, the continuousforming apparatus 300 is similar to the continuous forming apparatus 250of FIGS. 7 and 8 and includes a first endless belt 302, a second endlessbelt 304, a third endless belt 306, a fourth endless belt 308 (shown inFIG. 13), a first plurality of cleats 310, a second plurality of cleats312, a first frame 314, and a second frame 316. The continuous formingapparatus 300 may also include a third plurality of cleats 318 and afourth plurality of cleats 320 (shown in FIG. 13).

FIG. 13 is a top view of the continuous forming apparatus 300 of FIG. 12with the second endless belt 304 and second plurality of cleats 312removed to more clearly show the third plurality of cleats 318 and thefourth plurality of cleats 320. The continuous forming apparatus 300 mayalso include a third frame 322 and a fourth frame 324 for respectivelysupporting the third plurality of cleats 318 and the fourth plurality ofcleats 320 in molding a foaming material.

FIG. 14 is a cross sectional view along line 14-14 of the continuousforming apparatus 300 of FIG. 12. As shown, the first endless belt 302,the second endless belt 304, the third endless belt 306, and the fourthendless belt 308 include flat molding surfaces 326 used to define a moldcavity 328 and mold the foaming material 329. As the endless belts 302,304, 306, 308 are brought together to form the mold cavity 328, thethird endless belt 306 and the fourth endless belt 308 are slightlycompressed edgewise by the first endless belt 302 and the second endlessbelt 304 to create a seal between endless belts 302, 304, 306, 308 andthereby prevent the escape of expanding foaming material 329.

The first plurality of cleats 310 and the second plurality of cleats 312may include a three dimensional abutment surface 330. The abutmentsurfaces 330 of the first plurality of cleats 310 contacts and thesecond plurality of cleats 312 provides support to the first endlessbelt 302 and the second endless belt 304 in the lateral 138 andtransverse 114 directions.

The third plurality of cleats 318 and the fourth plurality of cleats 320may both include a flat abutment surface 332 and a neck 334 thatdisposes to engage and support the third endless belt 306 and the fourthendless belt 308 respectively. The neck 334 is narrow so that it mayextend between the first endless belt 302 and the second endless belt304 while providing transverse gaps 336 between the neck and the firstendless belt 302 and the second endless belt 304. The transverse gaps336 help to prevent the third plurality of cleats 318 and the fourthplurality of cleats 320 from binding with the first endless belt 302 andthe second endless belt 304.

This configuration may be used to produce large profiled foam product orproducts that require relatively long processing lengths. An addedadvantage of this configuration is that the distance between the thirdendless belt 306, the fourth endless belt 308, the third plurality ofcleats 318, the fourth plurality of cleats 320, the third frame 322, andthe fourth frame 324 may be adjusted, which allows the same equipment toproduce profiles of common depth but varying widths. For example, ifsynthetic lumber were being produced, the same continuous formingapparatus may be used to produce synthetic lumber in 2×2, 2×4, 2×6, 2×8,2×10 sizes with relatively minor adjustments to the continuous formingapparatus.

Each plurality of cleats 310, 312, 318, 320 may be moved or driven atthe same speed. The third plurality of cleats 318 and fourth pluralityof cleats 320 may be unpowered and idle, relying on the first pluralityof cleats 310 and the second plurality of cleats 312 and mold frictionto drag them along at the needed speed.

FIG. 15 is an elevated side view of another continuous forming apparatus400 according to the invention. As shown, the continuous formingapparatus 400 is similar to the continuous forming apparatus 100 of FIG.1 and includes a first endless belt 402, a second endless belt 404, afirst plurality of cleats 406, a second plurality of cleats 408, a firstframe 410, and a second frame 412. However, the first endless belt 402,the first plurality of cleats 406 and the first frame 410 are longerthan the second endless belt 404, the second plurality of cleats 408,and the second frame 412. Additionally, the continuous forming apparatus400 includes an insert placing means 414.

The difference in length between the first endless belt 402 and thesecond endless belt 404 permits the insert placing means 414 to placeinserts on the first endless belt 402. Before the first endless belt 402engages the second endless belt 404, the inserts are disposed within aclosed mold cavity of the continuous forming apparatus 400. Inserts mayinclude electrical wiring, threaded connectors, reinforcements,fasteners, and other items known in the art that may be molded into aproduct. The insert placing means 414 may be a person placing inserts byhand or an automated machine.

FIG. 16 is a cross sectional view of the first endless mold belt 402 offorming apparatus 400 of FIG. 15 along line 16-16 that illustrates thefirst endless belt 402 as including a mold cavity 420. As shown, inserts422 disposed within a mold cavity of the first endless belt 402.Additionally, slots 424 may be positioned in the wall 426 of the firstendless belt 402 in order to support and position the inserts 422 withinthe mold cavity 420. Mold slot covers 428 may be used to prevent foamingmaterial from contacting portions of the inserts 422 that extend intothe slots 424 and are to extend from the finished foam product.

FIG. 17 is a top view of the cross sectional view of FIG. 16 along line17-17. As shown, inserts 422 are disposed within the mold cavity 420 ofthe first endless belt 402. The inserts 422 extend into the slots 424 inthe wall 426. The slots 424 are filled by the mold slot covers 428.Additionally, the first endless belt 402 includes a mold wall 430 forseparating the first endless belt 402 into discrete mold cavities 420for making discrete products.

FIG. 18 is an exploded view of a cleat 500 of the invention. The cleat500 may include a mold support portion 502, a base portion 504, and anattachment mechanism 506. The mold support portion 502 includes anabutment surface 508 for engaging and supporting an endless belt.

The base portion 504 is removably attachable to the mold support portion502 by the attachment mechanism 506. This permits the mold supportportion 502 to be quickly and efficiently changed while leaving the baseportion 504 attached to an attachment chain. Thus, a mold supportportion 502 having a curved abutment surface 508 may be changed to anabutment surface 508 having flat surfaces and corners.

The attachment mechanism 506 may include threaded fasteners, clips,tongue and groove features, or other mechanical fasteners known in theart. Of course, the base portion 504 and the mold support portion 502may be integrally formed or welded together so that the attachmentmechanism 506 is no longer needed.

In conclusion, various configurations of continuous forming apparatusaccording to the invention have been disclosed. A continuous formingapparatus may be used in the production of a variety of foam productsincluding, but not limited to synthetic lumber, roofing, siding,interior molding & trim, panels, fencing, doors, window blind slats,etc. Furthermore, a continuous forming apparatus may be used to processfoam thermoplastics, foam thermoset plastics, foam ceramic or concretematerials, foam ceramic/plastic blends, and composites.

Generally, a continuous forming apparatus may include one or moreendless belts and a plurality of cleats for supporting the endless beltsand reducing the friction that results from operating the continuousforming apparatus. The endless belts help to define a product's shapeand texture. Additionally, the endless belts may incorporate localizedfeatures, such as pockets, ridges, knobs, clips, brackets, etc., in themold belt cavity may be used to locate and hold inserts in position thatwill be cast or molded into the product. The inserts may be embeddedinto the product for reinforcement, thread attachment, handles, hardpoints, wear plates, internal conduit or plumbing, electrical wiring, orany such characteristic that might enhance product performance oreliminate subsequent assembly.

Conventional laminated conveyor belts may be used as endless belts.Endless belts requiring greater thickness may be fabricated by casting arubber mold face onto an existing belt or fabric-reinforced carcass.Thicker endless belts may also have the mold surface or product-moldingcavity machined or otherwise carved into the belt face. Release films orlayers at the outer surfaces of the belts may also be incorporated intomold belts to facilitate release from the formed product.

The cleats used in the continuous forming apparatus may be made ofnearly any rigid or semi-rigid material such as metal, plastic, rubber,composite, ceramic, or a combination thereof. The cleats may incorporatea base that stays attached to the chain and an easily removable cleatprofile to facilitate changes in profile and product size. The cleatprofiles may include a radius, angle, or other feature on its abutmentsurface to allow an endless belt to easily center itself within thecleat. For example, the cleats 124, 126 and endless belts 120, 122 shownin FIG. 2 share angled sides that are wider at the opening to help theendless belts 120, 122 center and nest themselves into the cleats 124,126. Additionally, the profiles of opposed cleats may vary greatlydepending on the shape of the product and how the manufacturer prefersto divide the overall cavity. Furthermore, the cleats may be machined,molded, cast, extruded, or a combination thereof out of metal, plastic,rubber, composite, ceramic, or a combination of materials.

The use of high-strength chains and sprockets allow considerable pullingforce to be used in driving the continuous forming apparatus in thedirection of production. Furthermore, the rolling elements of theattachment chains contacting the rigid rails of the frames minimizefriction within the continuous forming apparatus and allow longer andwider belts to be driven and larger products processed. Additionally,the length of a continuous forming apparatus according to the inventionshould be long enough, and/or speed of the endless belts and pluralitiesof cleats slow enough, to assure that the foaming material issufficiently cooled and/or cured to maintain the desired shape of thefoam product when exiting the continuous forming apparatus.

The present invention may be embodied in other specific forms withoutdeparting from its structures, methods, or other essentialcharacteristics as broadly described herein and claimed hereinafter. Thedescribed embodiments are to be considered in all respects only asillustrative, and not restrictive. The scope of the invention is,therefore, indicated by the appended claims, rather than by theforegoing description. All changes that come within the meaning andrange of equivalency of the claims are to be embraced within theirscope.

1. A method of forming molded foam materials using a continuous formingapparatus comprising the steps of: providing a continuous formingapparatus comprising a first endless belt comprising an inner surfaceand an outer surface, a first plurality of cleats and a second pluralityof cleats opposed to the first plurality of cleats, wherein the firstplurality of cleats comprise a three-dimensional abutment surface toprovide transverse and lateral support to the first endless belt, and adrive mechanism for imparting motion to the first endless belt, thefirst plurality of cleats and the second plurality of cleats;introducing a composite material into a mold cavity defined at least inpart by the inner surface of the first endless belt; moving thecomposite material in a plane substantially parallel to the innersurface of the first endless belt; and curing the composite material toform a molded foam material.
 2. A method according to claim 1, whereinthe continuous forming apparatus further comprises a first attachmentchain connecting the first plurality of cleats together and a secondattachment chain connecting the second plurality of cleats together. 3.A method according to claim 1, wherein the continuous forming apparatusfurther comprises a second endless belt that cooperates with the firstendless belt to mold the foam material, wherein the second endless beltis supported by the second plurality of cleats.
 4. A method according toclaim 3, wherein the second plurality of cleats comprise athree-dimensional abutment surface to provide transverse and lateralsupport to second endless belt.
 5. A method according to claim 3,further comprising a third endless belt and a fourth endless belt thatcooperates with the first endless belt and the second endless belt tomold the foam material.
 6. A method according to claim 1, wherein thecontinuous forming apparatus further comprises a third plurality ofcleats and a fourth plurality of cleats disposed generally orthogonal tothe first plurality of cleats and the second plurality of cleats.
 7. Amethod according to claim 1, wherein the first endless belt of thecontinuous forming apparatus comprises an insert support feature.
 8. Amethod according to claim 1, wherein the first endless belt comprises amold cavity for molding a discrete foam part.
 9. A method according toclaim 1, wherein the continuous forming apparatus further comprises afirst frame disposed to support the first plurality of cleats and asecond frame disposed to support the second plurality of cleats.
 10. Amethod according to claim 1, wherein the first endless belt is supportedby the first plurality of cleats to form a curved cross sectional areafor molding foam material.
 11. A method according to claim 10, whereinthe first endless belt is also supported by the second plurality ofcleats to form a circular cross sectional area for molding foammaterial.
 12. A method according to claim 1, wherein a lateral gap isdisposed between each cleat of the first plurality of cleats.
 13. Amethod according to claim 1, wherein a transverse gap is disposedbetween the first plurality of cleats and the second plurality of cleatswhen the first plurality of cleats support the first endless belt formolding foam material.
 14. A method of forming molded foam materialsusing a continuous forming apparatus comprising the steps of: providinga continuous forming apparatus comprising a first endless beltcomprising an inner and an outer surface, a first plurality of cleats,wherein each cleat of the first plurality of cleats comprises a baseportion and a mold support portion, wherein the mold support portion isremovably attached to the base portion, wherein the mold support portioncomprises a three-dimensional abutment surface for supporting theendless belt, and a drive mechanism for imparting motion to the firstendless belt and the first plurality of cleats; introducing a compositematerial into a mold cavity defined at least in part by the innersurface of the first endless belt; moving the composite material throughthe continuous forming apparatus by longitudinal movement of the firstendless belt; and curing the composite material to form a molded foammaterial.
 15. A method according to claim 14, wherein the first endlessbelt comprises an insert support feature.
 16. A method according toclaim 14, wherein the first endless belt comprises a mold cavity formolding a discrete foam part.
 17. A method according to claim 14,wherein the continuous forming apparatus further comprises a first framedisposed to support the first plurality of cleats.
 18. A method offorming molded foam materials using a continuous forming apparatuscomprising the steps of: providing a continuous forming apparatuscomprising a first endless belt comprising an inner surface and an outersurface, a second endless belt comprising an inner surface and an outersurface, a first plurality of cleats and a second plurality of cleatsopposed to the first plurality of cleats, wherein the first plurality ofcleats supports the first endless belt in molding the foam material, athird endless belt and a fourth endless belt opposed to the thirdendless belt, wherein the third endless belt and the fourth endless beltare disposed substantially orthogonal to the first endless belt and thesecond endless belt, and a drive mechanism for imparting motion to thefirst endless belt, the second endless belt, the first plurality ofcleats, the second plurality of cleats, the third endless belt, and thefourth endless belt; introducing a composite material into a mold cavitydefined at least in part by the inner surface of the first endless beltand the inner surface of the second endless belt; moving the compositematerial through the continuous forming apparatus by longitudinalmovement of the first endless belt and the second endless belt; andcuring the composite material to form a molded foam material.
 19. Amethod according to claim 18, wherein the continuous forming apparatusfurther comprises a first attachment chain connecting the firstplurality of cleats together and a second attachment chain connectingthe second plurality of cleats together.
 20. A method according to claim18, wherein the continuous forming apparatus further comprises a thirdplurality of cleats and a fourth plurality of cleats that cooperate withthe first plurality of cleats and the second plurality of cleats to moldthe foam material, wherein the third endless belt is supported by thethird plurality of cleats and the fourth endless belt is supported bythe fourth plurality of cleats.